1. Field of the Invention
The present invention relates to a sensor material, a sensor, a detection method for a bio-substance and a detection method for transmitting light, and particularly, to a sensor material capable of reacting with various chemical materials or various bio-substances to detect an amount or the like of a material on the basis of a change in optical characteristic thereof, to a sensor, to a detection method for a bio-substance.
2. Description of the Background Art
A sensor (a biosensor) currently used for detecting a bio-substance is mainly constructed of a section producing a signal by use of a biochemical reaction and a signal converting section converting the signal to a current or the like. There have been available, as examples of such biosensors, an enzyme sensor utilizing an enzymatic reaction as a biochemical reaction, which is a biosensor for a clinical chemical analysis, an immunity sensor using an antigen or an antibody, and other sensors. An enzyme sensor is described which has a structure in which an enzyme film is fixedly mounted on a sensing surface of an electrode in S. Suzuki (Ed.), BIOSENSOR, Tokyo, Kodansha, 1984; pp. 91 to 102.
Theses biosensors have, in principle, had drawbacks that a measuring apparatus such as an ammeter is required, leading to not only high cost but also large working space required when used.
As a simple and convenient biosensor with no such drawbacks, there has been known a smell sensor, as disclosed in Japanese Published Unexamined Patent Application No. Hei 8-201296, in which an antibody against an odorant is dispersed in agar. The smell sensor detects a smell on the basis of a change in light transmittance in the agar due to agglomerates of the antibody and the odorant produced through an interaction therebetween.
Further, as materials that are expected to be utilized as a biosensor according to a nature selectively responding to a specific bio-substance, there are named materials each including a bio-substance-response material in a stimulus-responsive high polymer. As an example thereof, there has been known a chemo-mechanical material formed by entrapping glucose oxidase and urease in network high polymer chains obtained by cross-linking a co-polymer constituted of N-isopropyl acrylamide (see E. Kokufuda, journal of Society of Environmental Science, Japan, Vol. 10, No. 2, pp. 173-187 (1997)). This material has a property that it shrinks by addition of glucose while swelling by addition of urea.
The smell sensor and the chemo-mechanical material responding to a bio-substance have various problems on which improvement is to be performed in order to utilize them as biosensors.
A smell sensor disclosed in Japanese Published Unexamined Patent Application No. Hei 8-201296 detects a smell only on the basis of a change in transmittance caused by agglomerates of an antibody and an odorant; therefore, its sensitivity is so poor that difficulty has occurred in quantification of a concentration of the odorant.
Furthermore, while a chemo-mechanical material can be adapted to more of various bio-material-responsive materials than can a smell sensor, a change in volume is hard to be visually recognized in a case where it is used as a simple and easy biosensor like a smell sensor, resulting in a problem of difficulty in quantification of a concentration of a bio-substance.
The present invention has been made in view of above circumstances and provides a sensor material that requires no measuring apparatus having been required mainly for a biosensor, when used in a sensor, the sensor being capable of being utilized as a low-cost, simple and easy sensor, being more suited for quantification of a concentration of a bio-substance than is a smell sensor and being further capable of detecting various bio-substances, the sensor and a detection method for a bio-substance, all using the sensor material.
The present invention has been made in view of the above circumstances and will be shown below. That is, one aspect of the present invention is directed to a sensor material including at least a stimulus-responsive high polymer gel, a bio-substance-responsive material and a light modulation material.
Another aspect of the present invention is directed to a sensor material, in which at least the bio-substance-responsive material and the light modulation material are present inside the stimulus-responsive high polymer gel.
Another aspect of the present invention is directed to a sensor material, in which the light modulation material is present inside the stimulus-responsive high polymer gel while the bio-substance-responsive material is present outside the stimulus-responsive high polymer gel.
Another aspect of the present invention is directed to a sensor material, in which the stimulus-responsive high polymer gel swells or shrinks according to a concentration of the bio-substance.
Another aspect of the present invention is directed to a sensor material, in which a concentration of the light modulation material included in the stimulus-responsive high polymer gel is equal to or higher than a saturated absorption concentration or a saturated scattering concentration when the stimulus-responsive high polymer gel shrinks.
Another aspect of the present invention is directed to a sensor material, in which a ratio of a volume of the stimulus-responsive high polymer gel when in swelling to a volume of the stimulus-responsive high polymer gel when in shrinking is 5 or more.
Another aspect of the present invention is directed to a sensor having at least one of the above sensor materials and an optical waveguide.
Another aspect of the present invention is directed to a detection method for a bio-substance using one of the above sensor materials, in which a change in tone is detected on the basis of swelling or shrinking of the stimulus-responsive high polymer gel.
Another aspect of the present invention is directed to a detection method using the stimulus-responsive high polymer gel for detecting a bio-substance, in which a transmitting light therethrough is detected on the basis of swelling or shrinking of the stimulus-responsive high polymer gel.